CN220368511U - Battery charging device and voltage sag test system - Google Patents

Abstract

The utility model provides a battery charging device and a voltage sag test system, and relates to the technical field of power electronics. The battery charging device comprises a flyback circuit module, a rectifying circuit module, a driving chip, an undervoltage comparison circuit module, a first feedback circuit module and a chip backup power supply control circuit module; the flyback circuit module is respectively and electrically connected with the rectifying circuit module and the driving chip; the under-voltage comparison circuit module is electrically connected to the output end of the rectification circuit module, the under-voltage comparison circuit module, the first feedback circuit module and the chip backup power supply control circuit module are sequentially electrically connected, and the chip backup power supply control circuit module is electrically connected with the driving chip. When the battery charging device is subjected to the voltage sag three-stage test, the condition of charging interruption cannot occur, and the failure of the voltage sag three-stage test can be avoided.

Description

Battery charging device and voltage sag test system

Technical Field

The utility model relates to the technical field of power electronics, in particular to a battery charging device and a voltage sag test system.

Background

When the power grid and the power equipment are short-circuited or the load is greatly changed, the phenomena of AC voltage sag, short interruption and the like can be caused. At this time, the electric and electronic devices as the grid load may be affected by a sag, a short-time interruption, or a voltage change of the power supply. The voltage sag is that the voltage at a certain point of an electric power supply system suddenly drops to a specified threshold value and then returns to a normal value after a short interval.

The battery charging device belongs to equipment connected with a low-voltage power supply grid, and is required to be subjected to voltage sag, short interruption and voltage change immunity tests according to electromagnetic compatibility tests and measurement technologies before use. In the voltage sag test, a drop to 0% of the nominal operating voltage corresponds to a complete voltage interruption. The lower the voltage sag value, the more stringent the requirements on the electrical and electronic equipment.

When the voltage sag three-stage test is carried out on the existing flyback battery charging device, the voltage needs to be reduced to 40% of rated working voltage, namely alternating current 88V, and the duration is ten cycles, namely 200ms. At this time, the flyback battery charging device cannot continuously charge the battery, so that the charging is interrupted, and the voltage sag three-stage test is disabled.

Disclosure of Invention

In order to solve the problems in the prior art, it is an object of the present utility model to provide a battery charging device.

The utility model provides the following technical scheme:

a battery charging device comprises a flyback circuit module, a rectifying circuit module, a driving chip, an undervoltage comparison circuit module, a first feedback circuit module and a chip backup power supply control circuit module;

the flyback circuit module is electrically connected with the rectifying circuit module and the driving chip respectively;

the under-voltage comparison circuit module is electrically connected to the output end of the rectification circuit module, the under-voltage comparison circuit module, the first feedback circuit module and the chip backup power supply control circuit module are sequentially electrically connected, and the chip backup power supply control circuit module is electrically connected with the driving chip.

As a further alternative to the battery charging apparatus, the under-voltage comparing circuit module outputs a high-level signal when the output voltage of the rectifying circuit module is higher than a preset voltage value, and outputs a low-level signal when the output voltage is not higher than the preset voltage value.

As a further alternative to the battery charging device, the under-voltage comparison circuit module includes an operational amplifier, a first diode, a first resistor, a first capacitor, a second resistor, and an adjustable precision reference source;

the positive input end of the operational amplifier is electrically connected with the output end of the rectifying circuit module, one end of the first resistor and one end of the first capacitor, the negative input end of the operational amplifier is electrically connected with the other end of the first capacitor, one end of the second resistor and the reference electrode of the adjustable precision reference source, and the output end of the operational amplifier is electrically connected with the first feedback circuit module and the positive electrode of the first diode;

the other end of the second resistor is electrically connected with a first power supply, the anode of the adjustable precision reference source is grounded, and the cathode of the first diode is electrically connected with the other end of the first resistor.

As a further alternative to the battery charging device, the undervoltage comparison circuit module further includes a first voltage dividing resistor and a second voltage dividing resistor;

one end of the first voltage dividing resistor is electrically connected with the output end of the rectifying circuit module, the other end of the first voltage dividing resistor is electrically connected with one end of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is grounded;

the positive input end of the operational amplifier is electrically connected with the other end of the first voltage dividing resistor.

As a further alternative to the battery charging device, the first feedback circuit module includes a second diode, a photo coupler, a third resistor, a fourth resistor, and a fifth resistor;

the cathode of the second diode is electrically connected with the undervoltage comparison circuit module, and the anode of the second diode is electrically connected with a second pin of the photoelectric coupler;

the first pin of the photoelectric coupler is electrically connected with one end of a third resistor, and the other end of the third resistor is electrically connected with a first power supply;

the third pin of the photoelectric coupler is electrically connected with one end of the fourth resistor, and the other end of the fourth resistor is electrically connected with the chip backup power supply control circuit module;

the fourth pin of the photoelectric coupler is electrically connected with one end of the fifth resistor, and the other end of the fifth resistor is electrically connected with a second power supply.

As a further alternative scheme for the battery charging device, the chip backup power supply control circuit module includes a first triode, a second triode, a third triode, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a second capacitor, a third capacitor and a third diode;

the first pin of the first triode is electrically connected to the first feedback circuit module, one end of the sixth resistor, one end of the seventh resistor and one end of the second capacitor, the second pin of the first triode is electrically connected to the other end of the sixth resistor and the other end of the second capacitor and grounded, and the third pin of the first triode is electrically connected to one end of the eighth resistor and the negative electrode of the third diode;

the first pin of the second triode is electrically connected with the other end of the eighth resistor, one end of the ninth resistor and one end of the third capacitor, the second pin of the second triode is electrically connected with the other end of the ninth resistor and the other end of the third capacitor and is electrically connected with a second power supply, and the third pin of the second triode is electrically connected with the other end of the seventh resistor;

the first pin of the third triode is electrically connected with the positive electrode of the third diode and one end of the tenth resistor, the second pin of the third triode is electrically connected with the other end of the tenth resistor and the second power supply, and the third pin of the third triode is electrically connected with the driving chip.

As a further alternative to the battery charging device, the battery charging device further comprises a high frequency isolation inductor, and the first power source supplies power to a secondary side auxiliary winding of the high frequency isolation inductor.

As a further alternative to the battery charging device, the battery charging device further includes a PFC circuit module, and the second power supply supplies power to an auxiliary winding of the PFC circuit module.

As a further alternative to the battery charging device, the battery charging device further includes a current sampling circuit module, a voltage loop module, a sampling control module, and a second feedback circuit module;

the input end of the current sampling circuit module and the input end of the voltage loop module are electrically connected to the output end of the rectifying circuit module, and the output end of the current sampling circuit module and the output end of the voltage loop module are electrically connected to the input end of the sampling control module;

and the output end of the sampling control module is electrically connected with the driving chip through the voltage loop module and the second feedback circuit module in sequence.

It is another object of the present utility model to provide a voltage sag test system.

The utility model provides the following technical scheme:

a voltage sag test system comprises voltage sag test equipment, a battery and the battery charging device;

the voltage drop test equipment is electrically connected with the flyback circuit module, and the output end of the rectifying circuit module is electrically connected with the battery.

The embodiment of the utility model has the following beneficial effects:

when the battery charging device is subjected to a voltage sag three-stage test, the output voltage of the rectifying circuit module is reduced. At this time, the under-voltage comparison circuit module senses the output voltage variation of the rectification circuit module and outputs a signal to the first feedback circuit module. The first feedback circuit module further feeds back signals to the chip backup power supply control circuit module, the chip backup power supply control circuit module supplies power to the driving chip, normal operation of the driving chip is guaranteed, the situation of charging interruption is avoided, and further failure of a voltage sag three-stage test is avoided.

In order to make the above objects, features and advantages of the present utility model more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram showing an overall structure of a battery charging device according to an embodiment of the present utility model;

fig. 2 is a schematic structural diagram of an undervoltage comparison circuit module in a battery charging device according to an embodiment of the present utility model;

fig. 3 is a schematic structural diagram of a first feedback circuit module in a battery charging device according to an embodiment of the present utility model;

fig. 4 is a schematic structural diagram of a chip backup power supply control circuit module in a battery charging device according to an embodiment of the present utility model;

fig. 5 shows a waveform diagram of an output current of a battery charging device according to an embodiment of the present utility model when performing a voltage sag three-stage test;

fig. 6 shows waveforms of output currents when a conventional battery charging device performs a voltage sag three-stage test.

Description of main reference numerals:

10-battery; 100-EMC and rectifying and filtering circuit module; 200-PFC circuit module; 300-flyback circuit module; 400-high frequency isolation inductor; 500-rectifying circuit module; 600-driving chip; 700-undervoltage comparison circuit module; 710-an operational amplifier; 720-a first diode; 730-a first resistor; 740-a first capacitance; 750-a second resistance; 760-an adjustable precision reference source; 770-a first voltage dividing resistor; 780-a second voltage divider resistor; 800-a first feedback circuit module; 810-a second diode; 820-optocoupler; 830-a third resistance; 840-fourth resistance; 850-fifth resistor; 900-a chip backup power supply control circuit module; 910-a first triode; 920-second transistor; 930-a third transistor; 940-sixth resistance; 950-seventh resistance; 960-eighth resistance; 970-ninth resistance; 980-tenth resistor; 990-second capacitance; 9100-third capacitance; 9110-a third diode; 1000-a current sampling circuit module; 1100-a voltage loop module; 1200-a sampling control module; 1300-a second feedback circuit module.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Examples

Referring to fig. 1, the present embodiment provides a battery charging apparatus, and in particular, a flyback battery charging apparatus for preventing failure of a voltage sag test, which is used for charging a battery 10. The battery charging apparatus includes an EMC and rectifying filter circuit module 100, a PFC circuit module 200, a flyback circuit module 300, a high-frequency isolation inductor 400, a rectifying circuit module 500, a driving chip 600, an under-voltage comparison circuit module 700, a first feedback circuit module 800, a chip backup power supply control circuit module 900, a current sampling circuit module 1000, a voltage loop module 1100, a sampling control module 1200, and a second feedback circuit module 1300.

The EMC and rectifying filter circuit module 100, PFC circuit module 200, flyback circuit module 300, high-frequency isolation inductor 400, and rectifying circuit module 500 are electrically connected in this order.

In operation, the EMC and rectifying and filtering circuit module 100 is capable of filtering out conducted interference radiation in the battery charging device and converting ac power provided by the low voltage power supply grid into dc power. The PFC circuit module 200 converts the dc power into 400V dc power, and the flyback circuit module 300 and the high-frequency isolation inductor 400 convert the 400V dc power into dc power compatible with the battery 10, and finally output from the rectifying circuit module 500.

In addition, the input end of the current sampling circuit module 1000 and the input end of the voltage loop module 1100 are both electrically connected to the output end of the rectifying circuit module 500, and the output end of the current sampling circuit module 1000 and the output end of the voltage loop module 1100 are both electrically connected to the input end of the sampling control module 1200. The output end of the sampling control module 1200 is electrically connected with the driving chip 600 through the voltage loop module 1100 and the second feedback circuit module 1300 in sequence, and the driving chip 600 is electrically connected with the flyback circuit module 300.

In operation, the current sampling circuit module 1000 collects charging current information and transmits the charging current information to the sampling control module 1200. The voltage loop module 1100 collects the charging voltage information and transmits the charging voltage information to the sampling control module 1200. The charging current information and the charging voltage information provide a source of the synthesized PWM wave for the MCU algorithm of the sampling control module 1200, and the sampling control module 1200 further outputs the PWM wave to the voltage loop module 1100 to the outside and transmits the PWM wave to the driving chip 600 through the second feedback circuit module 1300. Finally, the driving chip 600 controls the primary winding of the flyback circuit module 300 according to the PWM wave.

When the voltage sag three-stage test is performed without considering the under-voltage comparing circuit module 700, the first feedback circuit module 800 and the chip backup power supply control circuit module 900, a voltage sag test device with an alternating-current voltage sag duration of 88V of 200ms is applied to the input end of the EMC and rectifying and filtering circuit module 100, so that the voltage of the direct-current bus of the PFC circuit module 200 is reduced, and the voltage of the secondary side of the high-frequency isolation inductor 400 is reduced along with the voltage of the direct-current bus. At this time, the output voltage of the rectifying circuit module 500 decreases, the driving chip 600 working voltage required by the primary winding of the flyback circuit module 300 cannot be provided, the driving chip 600 cannot output PWM waves, and the charging is interrupted, and finally, the voltage sag three-stage test fails.

In order to solve the problem, the battery charging device adopts the under-voltage comparison circuit module 700, the first feedback circuit module 800 and the chip backup power supply control circuit module 900, and plays an important supporting role in the test of the duration of 88V of the alternating voltage sag for 200ms.

The under-voltage comparison circuit module 700 is electrically connected to the output end of the rectifying circuit module 500, the under-voltage comparison circuit module 700, the first feedback circuit module 800 and the chip backup power supply control circuit module 900 are sequentially electrically connected, and the chip backup power supply control circuit module 900 is electrically connected to the driving chip 600.

When the above-described battery charging apparatus is subjected to the voltage sag three-stage test, the output voltage of the rectifier circuit module 500 decreases. At this time, the under-voltage comparing circuit module 700 senses that the output voltage of the rectifying circuit module 500 is reduced to a preset voltage value, and outputs a signal to the first feedback circuit module 800. The first feedback circuit module 800 further feeds back signals to the chip backup power supply control circuit module 900, and the chip backup power supply control circuit module 900 supplies power to the driving chip 600, so that the driving chip 600 is ensured to normally operate, the condition of charging interruption is avoided, and further, the failure of the voltage sag three-stage test is avoided.

In the present embodiment, the under-voltage comparing circuit module 700 outputs a high level signal when the output voltage of the rectifying circuit module 500 is higher than a preset voltage value, and outputs a low level signal when the output voltage is reduced and is lower than the preset voltage value.

Referring to fig. 2, in particular, the under-voltage comparison circuit module 700 includes an operational amplifier 710, a first diode 720, a first resistor 730, a first capacitor 740, a second resistor 750, and an adjustable precision reference source 760.

The positive input end of the operational amplifier 710 is electrically connected to the output end of the rectifying circuit module 500, one end of the first resistor 730 and one end of the first capacitor 740, the negative input end of the operational amplifier 710 is electrically connected to the other end of the first capacitor 740, one end of the second resistor 750 and the reference electrode of the adjustable precision reference source 760, and the output end of the operational amplifier 710 is electrically connected to the first feedback circuit module 800 and the positive electrode of the first diode 720.

In addition, the other end of the second resistor 750 is electrically connected to a first power source. The anode of the adjustable precision reference source 760 is grounded and a 2.5V reference voltage is provided by the reference electrode of the adjustable precision reference source 760. The cathode of the first diode 720 is electrically connected to the other end of the first resistor 730, and the first diode 720 and the first resistor 730 play a role in hysteresis comparison.

In a normal operating state, the output voltage of the rectifying circuit module 500 is higher than a preset voltage value, and the output terminal of the operational amplifier 710 outputs a high level. When the voltage sag three-stage test is performed, the output voltage of the rectifying circuit module 500 drops to a preset voltage value, and the output terminal of the operational amplifier 710 outputs a low level.

In some embodiments, the first power source supplies the secondary auxiliary winding of the high frequency isolation inductor 400 at a voltage level of 12V.

Further, the under-voltage comparison circuit module 700 further includes a first voltage dividing resistor 770 and a second voltage dividing resistor 780.

One end of the first voltage dividing resistor 770 is electrically connected to the output end of the rectifying circuit module 500, the other end of the first voltage dividing resistor 770 is electrically connected to one end of the second voltage dividing resistor 780, and the other end of the second voltage dividing resistor 780 is grounded. In addition, the positive input terminal of the operational amplifier 710 is electrically connected to the other terminal of the first voltage dividing resistor 770.

At this time, the first voltage dividing resistor 770 and the second voltage dividing resistor 780 divide the output voltage of the rectifying circuit module 500, so that a constant proportional relationship is formed between the voltage signal connected to the positive input terminal of the operational amplifier 710 and the output voltage of the rectifying circuit module 500.

Referring to fig. 3, specifically, the first feedback circuit module 800 is composed of a second diode 810, a photo coupler 820, a third resistor 830, a fourth resistor 840 and a fifth resistor 850.

Wherein, the negative electrode of the second diode 810 is electrically connected to the output terminal of the operational amplifier 710, and the positive electrode of the second diode 810 is electrically connected to the second pin of the photo coupler 820.

In addition, the first pin of the optocoupler 820 is electrically connected to one end of the third resistor 830, and the other end of the third resistor 830 is electrically connected to the first power source. The third leg of the optocoupler 820 is electrically connected to one end of the fourth resistor 840, and the other end of the fourth resistor 840 is electrically connected to the chip back-up power supply control circuit module 900. The fourth pin of the optocoupler 820 is electrically connected to one end of the fifth resistor 850, and the other end of the fifth resistor 850 is electrically connected to a second power source.

Under normal operation, the output of the operational amplifier 710 outputs a high level. At this time, the second leg of the photo coupler 820 is turned off, and the third leg of the photo coupler 820 is also turned off.

The output of op-amp 710 outputs a low level when performing a voltage sag three-stage test. At this time, the second leg of the photo coupler 820 is turned on, and the third leg of the photo coupler 820 is also turned on.

In some embodiments, the second power source supplies power to the auxiliary winding of PFC circuit module 200 and has a voltage value of 18V. PFC circuit module 200 provides auxiliary winding power for a longer duration than the primary side auxiliary winding power of high frequency isolation inductor 400, which is capable of withstanding the most severe level of voltage sag test criteria.

Referring to fig. 4, specifically, the chip standby power supply control circuit module 900 is composed of a first triode 910, a second triode 920, a third triode 930, a sixth resistor 940, a seventh resistor 950, an eighth resistor 960, a ninth resistor 970, a tenth resistor 980, a second capacitor 990, a third capacitor 9100, and a third diode 9110.

The first pin of the first triode 910 is electrically connected to the other end of the fourth resistor 840, one end of the sixth resistor 940, one end of the seventh resistor 950 and one end of the second capacitor 990. The second leg of the first transistor 910 is electrically connected to the other end of the sixth resistor 940 and the other end of the second capacitor 990 and is grounded. The third leg of the first transistor 910 is electrically connected to one end of the eighth resistor 960 and the cathode of the third diode 9110.

The first leg of the second transistor 920 is electrically connected to the other end of the eighth resistor 960, one end of the ninth resistor 970, and one end of the third capacitor 9100. The second leg of the second transistor 920 is electrically connected to the other end of the ninth resistor 970, the other end of the third capacitor 9100, and a second power supply. The third leg of the second transistor 920 is electrically connected to the other end of the seventh resistor 950.

The first pin of the third triode 930 is electrically connected to the positive electrode of the third diode 9110 and one end of the tenth resistor 980, the second pin of the third triode 930 is electrically connected to the other end of the tenth resistor 980 and the second power supply, and the third pin of the third triode 930 is electrically connected to the driving chip 600.

Under normal operation, the third leg of the optocoupler 820 is turned off. At this time, the emitter and collector of the first transistor 910 are turned off, the emitter and collector of the third transistor 930 are turned off, and the chip standby power supply control circuit module 900 does not operate.

The third leg of the optocoupler 820 is turned on when the voltage sag three-stage test is performed. At this time, the emitter and collector of the first transistor 910 are turned on, the emitter and collector of the third transistor 930 are turned on, and the chip standby power supply control circuit module 900 operates to provide standby power for the driving chip 600, so that the charging process is continuous.

In a word, when carrying out the tertiary test of voltage sag to above-mentioned battery charging device, the condition that charges and break can not appear, can avoid the tertiary test inefficacy of voltage sag.

The embodiment also provides a voltage sag test system, which comprises voltage sag test equipment, a battery 10 and the battery charging device.

The voltage drop test device is electrically connected with the EMC and rectifying filter circuit module 100, and further electrically connected with the PFC circuit module 200, the flyback circuit module 300, and the like. The output terminal of the rectifying circuit module 500 is electrically connected to the battery 10, and charges the battery 10.

Referring to fig. 5, when the under-voltage comparing circuit module 700, the first feedback circuit module 800 and the chip backup power supply controlling circuit module 900 are provided to perform the voltage sag three-stage test, the charging current at the output end of the rectifying circuit module 500 is only slightly fluctuated compared with the normal value.

Referring to fig. 6, in contrast, if the voltage sag three-stage test is performed without the under-voltage comparing circuit module 700, the first feedback circuit module 800 and the chip backup power supply control circuit module 900, the current probe electrically connected to the output end of the rectifying circuit module 500 is based on the electromagnetic induction principle, and when the voltage sag test device generates the transient ac voltage change, the current probe instantaneously attenuates to be a negative value at the display value of the oscilloscope.

Any particular values in all examples shown and described herein are to be construed as merely illustrative and not a limitation, and thus other examples of exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

The above examples merely represent a few embodiments of the present utility model, which are described in more detail and are not to be construed as limiting the scope of the present utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model.

Claims (10)

1. The battery charging device is characterized by comprising a flyback circuit module, a rectifying circuit module, a driving chip, an undervoltage comparison circuit module, a first feedback circuit module and a chip backup power supply control circuit module;

the flyback circuit module is electrically connected with the rectifying circuit module and the driving chip respectively;

the under-voltage comparison circuit module is electrically connected to the output end of the rectification circuit module, the under-voltage comparison circuit module, the first feedback circuit module and the chip backup power supply control circuit module are sequentially electrically connected, and the chip backup power supply control circuit module is electrically connected with the driving chip.

2. The battery charging apparatus according to claim 1, wherein the under-voltage comparing circuit module outputs a high level signal when an output voltage of the rectifying circuit module is higher than a preset voltage value, and outputs a low level signal when the output voltage is not higher than the preset voltage value.

3. The battery charging apparatus of claim 2, wherein the under-voltage comparison circuit module comprises an operational amplifier, a first diode, a first resistor, a first capacitor, a second resistor, and an adjustable precision reference source;

the positive input end of the operational amplifier is electrically connected with the output end of the rectifying circuit module, one end of the first resistor and one end of the first capacitor, the negative input end of the operational amplifier is electrically connected with the other end of the first capacitor, one end of the second resistor and the reference electrode of the adjustable precision reference source, and the output end of the operational amplifier is electrically connected with the first feedback circuit module and the positive electrode of the first diode;

the other end of the second resistor is electrically connected with a first power supply, the anode of the adjustable precision reference source is grounded, and the cathode of the first diode is electrically connected with the other end of the first resistor.

4. The battery charging apparatus of claim 3, wherein the brown-out comparison circuit module further comprises a first voltage divider resistor and a second voltage divider resistor;

one end of the first voltage dividing resistor is electrically connected with the output end of the rectifying circuit module, the other end of the first voltage dividing resistor is electrically connected with one end of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is grounded;

the positive input end of the operational amplifier is electrically connected with the other end of the first voltage dividing resistor.

5. The battery charging apparatus of claim 1, wherein the first feedback circuit module comprises a second diode, a photo coupler, a third resistor, a fourth resistor, and a fifth resistor;

the cathode of the second diode is electrically connected with the undervoltage comparison circuit module, and the anode of the second diode is electrically connected with a second pin of the photoelectric coupler;

the first pin of the photoelectric coupler is electrically connected with one end of a third resistor, and the other end of the third resistor is electrically connected with a first power supply;

the third pin of the photoelectric coupler is electrically connected with one end of the fourth resistor, and the other end of the fourth resistor is electrically connected with the chip backup power supply control circuit module;

the fourth pin of the photoelectric coupler is electrically connected with one end of the fifth resistor, and the other end of the fifth resistor is electrically connected with a second power supply.

6. The battery charging apparatus of claim 1, wherein the chip back-up power supply control circuit module comprises a first transistor, a second transistor, a third transistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a second capacitor, a third capacitor, and a third diode;

the first pin of the first triode is electrically connected to the first feedback circuit module, one end of the sixth resistor, one end of the seventh resistor and one end of the second capacitor, the second pin of the first triode is electrically connected to the other end of the sixth resistor and the other end of the second capacitor and grounded, and the third pin of the first triode is electrically connected to one end of the eighth resistor and the negative electrode of the third diode;

the first pin of the second triode is electrically connected with the other end of the eighth resistor, one end of the ninth resistor and one end of the third capacitor, the second pin of the second triode is electrically connected with the other end of the ninth resistor and the other end of the third capacitor and is electrically connected with a second power supply, and the third pin of the second triode is electrically connected with the other end of the seventh resistor;

the first pin of the third triode is electrically connected with the positive electrode of the third diode and one end of the tenth resistor, the second pin of the third triode is electrically connected with the other end of the tenth resistor and the second power supply, and the third pin of the third triode is electrically connected with the driving chip.

7. The battery charging apparatus of claim 3, 4 or 5, further comprising a high frequency isolation inductor, the first power source supplying power to a secondary auxiliary winding of the high frequency isolation inductor.

8. The battery charging apparatus of claim 5 or 6, further comprising a PFC circuit module, the second power source supplying power to auxiliary windings of the PFC circuit module.

9. The battery charging apparatus of any one of claims 1-6, further comprising a current sampling circuit module, a voltage loop module, a sampling control module, and a second feedback circuit module;

the input end of the current sampling circuit module and the input end of the voltage loop module are electrically connected to the output end of the rectifying circuit module, and the output end of the current sampling circuit module and the output end of the voltage loop module are electrically connected to the input end of the sampling control module;

and the output end of the sampling control module is electrically connected with the driving chip through the voltage loop module and the second feedback circuit module in sequence.

10. A voltage sag test system comprising a voltage sag test device, a battery, and a battery charging apparatus according to any one of claims 1-9;

the voltage drop test equipment is electrically connected with the flyback circuit module, and the output end of the rectifying circuit module is electrically connected with the battery.